In some image forming substance cartridges, an image forming substance sump or reservoir may be used to retain the image forming substance until the image forming substance may be required by the developer system. Inside of the image forming substance sump may be an agitating device, such as a paddle, to agitate and aid in the removal of image forming substance from the sump. In some cases, however, the agitating device may not be capable of reaching a substantial portion of the interior surface of the sump, which may be due, for example, to the geometry of the cartridge or due to poor image forming substance flow properties.